The subject matter of the present invention relates to a shock absorber for a perforating gun, and more particularly, to a shock absorber incorporated in a perforating gun string which includes a collapsible energy absorbing element adapted to permanently deform when absorbing shock.
Perforating guns are adapted to be disposed in a wellbore for perforating a formation. Well fluids flow from the perforated formation. When the perforating gun fires, a shock is received in the tubing string above the perforating gun. A shock absorber is usually incorporated in the tubing string above the perforating gun for absorbing the shock. The shock absorber usually includes a spring which stores mechanical energy by compression in response to the shock and releases the mechanical energy by expansion following compression over a longer period of time such that the force exerted is reduced. Although this configuration absorbs mechanical energy associated with the shock, attempts to improve this shock absorber have focused on achieving a smoother release of the mechanical energy from the spring coil shock absorber system following storage of the mechanical energy. However, the problem associated with the release of the mechanical energy could be eliminated entirely if the absorbing element in the shock absorber did not expand following compression but, instead, released the stored energy in a different form, such as heat.